(a) Field of the Invention
The present invention relates to a liquid crystal display.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays (FPD). An LCD has two display panels on which field generating electrodes are formed with a liquid crystal layer interposed between the two display panels. A voltage is applied to the field generating electrodes to generate an electric field on the liquid crystal layer. The generated electric field determines the orientation of liquid crystal molecules of the liquid crystal layer and controls the polarization of incident light to display an image.
The liquid crystal layer is classified into various types according to the type of arrangement of the liquid crystal molecules. For example, there may be a twisted nematic (TN) mode, a vertical alignment (VA) mode, an in-plane switching (IPS) mode, etc.
In the twisted nematic mode, the long axes of liquid crystal molecules are arranged parallel to the substrate in the absence of an electric field and arranged perpendicular to the substrate by the electric field. When the liquid crystal molecules are aligned parallel to the substrate, the liquid crystal molecules are in a twisted state.
On the other hand, in a vertical alignment (VA) mode LCD, unlike the twisted nematic mode, the long axes of the liquid crystal molecules are arranged perpendicular to the substrate in the absence of the electric field and arranged perpendicular to the direction of the electric field when the electric field is applied.
In the in-plane switching mode LCD, two field generating electrodes are formed on one substrate, whereby an electric field may include directions different from the perpendicular or horizontal direction.
Among them, in an LCD of the vertical alignment (VA) mode or the nematic mode, as light polarized by a polarizer passes through the liquid crystal layer having optical anisotropy, the phase retardations differ according to the incident angle of the light such that a difference of the phase retardation is generated, thereby differentiating the transmittance according to the viewing angle.
Accordingly, a compensation film to compensate the difference of the phase retardation is used in the liquid crystal layer, thereby improving the viewing angle.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.